A preimplanatation genetic diagnosis (PGD) can affect a pregnancy in more ways than one. The diagnosis of a PGD can cause the donor or recipient of an embryo to carefully select the embryo chosen to be used for a pregnancy. Overall, however, PGD has very little effect on a pregnancy; in fact, a PGD could prove the final indicator that an individual or couple is infertile. Below is an explanation of PGD and what it can mean for any future preganancies.
Preimplantation Genetic Testing Explained
Preimplantation genetic testing is the process whereby an embryo’s DNA is tested to check for abnormalities. Individually, sperm and eggs only have one half of the required DNA to create an embryo. As such, testing them individually will not show whether abnormalities exist because on their own the DNA of egg and sperm is incomplete. Therefore, this testing is performed after the sperm and egg are combined. Each embryo is tested individually; therefore, one embryo found to have an abnormality does not mean that any further embryos will have the same abnormality.
The results of PGD can indicate whether the embryo will have any genetic abnormalities that could lead to it not being a viable embryo, and thereby unable to cause a pregnancy. PGD can also demonstrate whether the embryo will result in a handicapped child. However, PGD will also tell embryo owners about aspects of any future child it may develop, including eye color and gender. Therefore, PGD has several benefits.
The Controversy about PGD
PGD has many critics. Critics argue that PGD essentially permits embryo owners to hand-select their child. Not only that, they state it permits embryo owners to discard of those embryos considered “undesirable,” and that this label could apply to anything from a handicap to an embryo to the wrong gender. However, as PGD is a procedure, it has not been approved or rejected by the federal Food and Drug Administration (FDA). Therefore, the procedure is open to interested individuals.
Pregnancy after PGD
Many fertility specialists will require their patients to submit their embryos to PGD prior to implanting them in an In Vitro fertilization procedure or other fertilization procedure. Through PGD, a specialist can determine whether any genetic abnormalities may prevent a pregnancy from occurring. In this way, the specialist can eliminate genetic disorders as responsible or a potential cause of pregnancy failure.
Not finding a PGD abnormality and implanting that embryo, however, does not guarantee a successful pregnancy. There are, after all, many other reasons for infertility. PGD testing merely eliminates genetic disorders as a cause for miscarriage or infertility.
PGD and Abnormalities
Many times, abnormalities can occur in an implanted embryo that are not due to genetics or that are due to genetic changes occurring after implantation. PGD can only identify problems in embryos prior to implantation, and cannot reveal any problems that may develop due to abnormal genetic development. Therefore, PGD does not prevent the recipient of the embryo from miscarrying or continuing to have fertility problems. While pregnancy is possible, it is not guaranteed after PGD testing.